How to choose the 'Mr Right' of wheat cultivars

March 2016

This article highlights the choice of a suitable wheat cultivar as part of the general management of the wheat crop in a sustainable crop rotation system. The major consideration in wheat is to increase the competitiveness and profitability of production and this can only be achieved by maximising the yield potential of the crop/soil/climate combination, while input costs are strictly managed.

Cultivar choice

Cultivar choice is an important production decision and could contribute to reducing risk and optimising yields. The following guidelines must be considered when deciding on cultivar choice:

Identify the specific production area where wheat is to be planted, as this determines the adaptability and disease profile of suitable wheat cultivars. A list of bread wheat cultivars that are available for commercial purposes is published annually and is divided into three categories: cultivars for dry land production in the north, the southern production area and under irrigation.

Determine the sub-region where productions are to take place. Photoperiod and vernalisation control the growth period, and cultivars must be adapted to climatic conditions such as growing season length, rainfall pattern and temperature during the growing season, soil water availability at planting and the first and last frost dates. The evaluation of cultivars over time is reflected in the recommended optimum planting spectrum for each cultivar. Utilise this optimum planting spectrum in an area to minimise production risks like drought, disease occurrence and crop rotation time constraints.

Cultivars can adapt to specific yield potential conditions although the genetic yield potential of the available cultivars is higher than the yields currently realised under commercial conditions. These differences in yield are due to climatic and production conditions, crop management decisions, disease, insect and weed pressures. The ideal cultivar would yield the highest at all yield potential conditions indicating excellent adaptability.

In selecting the correct cultivar to produce in a specific region, it is thus important to take into account agronomic characteristics (lodging, shattering and aluminium tolerance), disease susceptibility (rusts and Fusarium spp.) and Russian wheat aphid resistance of cultivars where applicable.

Grading and quality of the bread wheat consists of four grades determined by the protein content, hectolitre mass and the falling number of the grain. Hectolitre mass and especially protein content are influenced by the environment, soil water and fertiliser management during the grain filling period up to maturity. All bread wheat cultivars released for production qualify for all grades depending on the protein content, hectolitre mass and falling number.

Conclusion

To conclude:

Plant a number of cultivars with a high yield potential and relevant disease and insect resistance.

Revise cultivar choice annually to adapt to changing circumstances and to consider new cultivars.

Use additional information/guidelines regarding cultivar characteristics, long-term yield data and relative yields that are available to the farmer.

Select the optimal planting time for the chosen cultivar, use high quality treated seed at the recommended seeding density to ensure optimal emergence and seedling establishment. Be aware of the coleoptile length of a cultivar when planting depth is increased in a dry seedbed.

Follow an effective spraying programme for the control of weeds, insects and diseases during the growing season and fertilise according to yield potential.

Timely harvest of the crop and post-harvest storage can impact on optimal yield and grain quality and on price per ton received.